Solid-state flash-disk devices use flash memory for storage rather than rotating disks. Eliminating the rotating disks and mechanical devices greatly improves reliability and shock resistance. However, these solid-state devices may be more prone to damage from tiny electrical shocks or electro-static-discharge (ESD).
Flash memory chips use electrically-erasable programmable read-only memory cells (EEPROM) that can only be read or written in blocks. The blocks are typically 512 bytes or larger. In contrast to block-addressable flash memory, static random-access memory (SRAM) and dynamic-random-access memory (DRAM) are usually byte-addressable or word-addressable, where words are 4 or 8 bytes.
The parent applications disclosed an electronic data storage medium that had fingerprint verification capability. FIG. 1 is a schematic circuit block diagram illustrating an electronic data storage medium disclosed in the parent application.
The electronic data storage medium with fingerprint verification capability can be accessed by external computer 9 using input/output interface circuit 5, which may use a Personal-Computer Memory Card International Association (PCMCIA), RS-232, or similar interface to communicate. The electronic data storage medium can be located inside or outside of the external computer.
The electronic data storage medium with fingerprint verification capability is packaged in card body 1, and includes processing unit 2, memory device 3, fingerprint sensor 4, input/output interface circuit 5, display unit 6, power source 7, and function key set 8.
Memory device 3 can be a flash memory device that stores data files. Fingerprint sensor 4 scans a fingerprint of a user to generate fingerprint scan data. Processing unit 2 connects to other components and can operate in various modes, such as a programming mode, a data retrieving mode, and a data resetting mode. Power source 7 supplies electrical power to processing unit 2. Function key set 8 allows the user to input a password that is verified by processing unit 2. Display unit 6 shows the operating status of the electronic data storage medium.
The electronic data storage medium may be a subset of the electronic data storage medium with fingerprint verification capability. The electronic data storage medium is packaged in card body 1, and includes processing unit 2, memory device 3, and input/output interface circuit 5. While such an electronic data storage medium is useful, manufacturing methods and product designs are desired that can be cost-effectively produced. In particular, designs for making the card body or casing that encapsulates the electronic components are desired. To reduce the cost and size, designs of the electronic data storage medium that eliminate some costly components, such as the fingerprint sensor, function key set, and display, are desirable. An external power source may further reduce costs and size. Such device designs can allow a low-cost electronic data storage medium to be manufactured.
While metal casings are inexpensive to manufacture, metal casings are more rugged and sturdy. Metal casings also conduct ESD currents from human touch. Grounding of these metal casings is especially useful.
What is desired is a solid-state flash-drive device that has improved electro-static-discharge (ESD) protection. A grounded metal-encased flash-drive is desired.